A framework strapdown inertial navigation system, it is characterized in that: it included high-speed isolation device and SINS system, the SINS system was installed in the middle of eccentric capsule through the transition frame, and the eccentric capsule was connected with transporting species through dead axle bearings and thrust plate, the overall gravity center of the SINS system and installed eccentric capsule was below the spin axis of the eccentric capsule, forming the restoring moment on the effect of gravity. This invention use the characteristics of bearings and gravity, reasonable design the structure so the eccentric capsule will not rotate with the rotation of transporting species, provide a good working environment for SINS system improve the system's measurement accuracy. The present invention applies to all low-flying transporters, especially to low-cost, miniaturized low-flying transporters with high spin velocity.